Anthropic 400: tools.N.custom.input_schema.type Field required (tool schema missing top-level type) #75

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1. seotk0319 commented on Jul 9, 2026

   

   seotk0319

   on Jul 9, 2026 – with ChatGPT Codex Connector

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   정정 / Correction — the type-only fix is not enough

   원래 제안한 "최상위 type 보정"만으로는 해결되지 않았습니다. Anthropic Messages API는 input_schema 루트에 oneOf/anyOf/allOf 콤비네이터가 있으면 그것도 거부합니다. Codex/OpenAI Responses 쪽 일부 툴(그리고 MCP 툴)이 루트에 union 스키마를 그대로 내보내는 경우가 있어서, type만 채워도 같은 400이 계속 납니다.

   Adding a top-level type alone does not fix it. The Anthropic Messages API also rejects a top-level oneOf/anyOf/allOf on input_schema. Some Codex/OpenAI Responses (and MCP) tools emit a root-level union schema, so filling in type still 400s.

   완전한 원인 / Full root cause

   • input_schema 루트에 type 누락 → 거부
   • input_schema 루트에 oneOf/anyOf/allOf 존재 → 거부 (프로퍼티 내부에 중첩된 anyOf 등은 허용)

   완전한 수정 / Complete fix (src/adapters/anthropic.ts)

   루트 콤비네이터를 평탄화합니다: 각 branch의 properties를 루트 object 스키마로 병합, required는 allOf에서만 병합(oneOf/anyOf는 과도 강제 방지), 중첩된 anyOf는 그대로 보존, 그 외 루트 키(title, additionalProperties 등)는 유지.

   // Anthropic requires every tool's `input_schema` to be a JSON Schema object with an
   // explicit top-level `type` (it validates `tools.N.custom.input_schema.type`). It also
   // rejects top-level oneOf/allOf/anyOf, even though Codex/OpenAI Responses tools may emit
   // them. Normalize only the root schema so missing/invalid `type` becomes an object and
   // root compositions are flattened while nested property schemas stay intact.
   function normalizeAnthropicInputSchema(schema: unknown): Record<string, unknown> {
     if (!schema || typeof schema !== "object" || Array.isArray(schema)) {
       return { type: "object", properties: {} };
     }
     const obj = schema as Record<string, unknown>;
     const compositionKeys = ["oneOf", "anyOf", "allOf"] as const;
     const hasRootComposition = compositionKeys.some(k => Array.isArray(obj[k]));
   
     if (!hasRootComposition) {
       const s: Record<string, unknown> = { ...obj };
       if (typeof s.type !== "string") s.type = "object";
       if (s.type === "object" && (s.properties === undefined || s.properties === null)) {
         s.properties = {};
       }
       return s;
     }
   
     const properties: Record<string, unknown> = {};
     const required = new Set<string>();
   
     if (obj.properties && typeof obj.properties === "object" && !Array.isArray(obj.properties)) {
       Object.assign(properties, obj.properties as Record<string, unknown>);
     }
     if (Array.isArray(obj.required)) {
       for (const item of obj.required) if (typeof item === "string") required.add(item);
     }
   
     for (const key of compositionKeys) {
       const variants = obj[key];
       if (!Array.isArray(variants)) continue;
       const mergeRequired = key === "allOf";
       for (const variant of variants) {
         if (!variant || typeof variant !== "object" || Array.isArray(variant)) continue;
         const v = variant as Record<string, unknown>;
         if (v.properties && typeof v.properties === "object" && !Array.isArray(v.properties)) {
           Object.assign(properties, v.properties as Record<string, unknown>);
         }
         if (mergeRequired && Array.isArray(v.required)) {
           for (const item of v.required) if (typeof item === "string") required.add(item);
         }
       }
     }
   
     const s: Record<string, unknown> = {};
     for (const [key, value] of Object.entries(obj)) {
       if (key === "oneOf" || key === "anyOf" || key === "allOf") continue;
       if (key === "type" || key === "properties" || key === "required") continue;
       s[key] = value;
     }
     s.type = "object";
     s.properties = properties;
     if (required.size > 0) s.required = [...required];
     return s;
   }

   toolsToAnthropicFormat 내부는 동일하게 input_schema: normalizeAnthropicInputSchema(t.parameters) 로 연결합니다.

   검증 / Verification

   파일에 적용한 실제 함수 본문을 그대로 실행하여 다음 케이스를 확인했습니다:

   • type 누락 → {type:"object",properties:{}}
   • root anyOf / oneOf → 각 branch properties 병합, required 강제 안 함
   • root allOf → properties + required 병합 (["p","r"])
   • nested anyOf (프로퍼티 내부) → 원형 그대로 보존
   • root union + 여분 키(title, additionalProperties) → 여분 키 유지, 콤비네이터만 제거

   이 상태에서 서브에이전트/브라우저/Codex 툴 호출이 모두 정상 동작합니다. Original title/body should be read together with this correction. Happy to open a PR with this complete version.
2. Ingwannu commented on Jul 9, 2026

   

   Ingwannu

   on Jul 9, 2026

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   Confirmed valid and opened a fix PR: #76

   What I verified:

   • Current dev was forwarding Anthropic input_schema: t.parameters verbatim.
   • A schema with properties/required but no root type stayed missing type.
   • A root anyOf schema also stayed at the root, matching the corrected report here.

   Fix in #76:

   • Normalize Anthropic tool input_schema to a root type: "object" schema.
   • Ensure properties exists.
   • Flatten root oneOf / anyOf / allOf while preserving nested property schemas.
   • Merge required only for allOf, not oneOf / anyOf.

   Validation:

   • bun test tests/anthropic-tool-schema.test.ts tests/anthropic-empty-content.test.ts tests/kiro-adapter.test.ts -> 38 pass
   • bun run typecheck -> pass
   • bun test ./tests/ -> 1677 pass, 0 fail

   The PR body includes Fixes #75, so this issue should close automatically when the PR is merged.
3. lidge-jun commented on Jul 9, 2026

   

   lidge-jun

   on Jul 9, 2026

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   Fixed and verified. The Anthropic adapter now normalizes tool input_schema roots so schemas without a top-level type are sent as object schemas, and the regression coverage is in tests/anthropic-tool-schema.test.ts.\n\nVerified locally with:\n- bun test tests/anthropic-tool-schema.test.ts tests/anthropic-empty-content.test.ts tests/kiro-adapter.test.ts\n- bun test tests/multi-agent-compat.test.ts tests/native-model-toggle.test.ts\n- npm run build (gui)\n- bun run typecheck\n\nAlso verified on dev Cross-platform CI: https://github.com/lidge-jun/opencodex/actions/runs/29034128441
4. lidge-jun

   closed this as completedon Jul 9, 2026